Process for upgrading a pentane-containing natural gasoline by isomerization and reforming



Feb. 7, 1961 2,970,955

A. CLARK PROCESS FOR UPGRADING A PENTANE-CONTAINING NATURAL GASOLINE BY ISOMERIZATION AND REFORMING Filed NOV.- 25, 1955 2 Sheets-Sheet 1 4* m aomvaa I n Q9 (\JL g X F) S N X X aomvau N 1 ML- X g 2. 2 k

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TORN S 2,970,955 PROCESS FOR UPGRADING A PENTANE-CON- TAINING NATURAL GASOLINE BY ISOMERIZA- TIGN AND REFORMENG Alfred Clark, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Nov. 25, 1955, Ser. No. 549,019 16 Claims. (Cl. 208-65) This invention relates to the catalytic treatment of a natural or straight-run gasoline or a component thereof. In one of its aspects the invention is concerned with a multi-stage reforming process in which isopentane or a fraction, say, an isopentane containing fraction, such as a straight-run gasoline or a C C, fraction from such a gasoline is catalytically isomerized, and isopentane or a fraction containing the same is removed from the catalytically isomerized gasoline, following which the remaining gasoline is further catalytically treated, or re formed, obtaining, upon the combination of said fraction and said further treated gasoline, a product of improved characteristics.

Thus, it is among the objects of this invention to provide an improved gasoline product from a natural or straight-run gasoline or a component thereof; to provide said improved gasoline by advantageous combination of a series of steps in a process for the treatment of a natural or straight-run gasoline or a component thereof in presence of a catalyst in said steps; and to accomplish a higher octane value product by obtaining during the processing of said natural or straight-run gasoline, or its component, as defined herein, of at least one fraction having a desirable blending value; a more specific object being the recovery of higher yields of isopentane in a final product gasoline. Other objects, aspects, and advantages of the invention are apparent from a study of this disclosure, drawing and the appended claims.

The term reforming is Well known in the petroleum industry and refers to the treatment of gasoline or fractions thereof to improve their anti-knock characteristics. The reforming process involves many reactions not all of which are entirely understood or even known. The primary known reactions comprise controlled or selective cracking and aromatization, the latter including dehydrogenation ofC naphthenic hydrocarbons to aromatics and the cyclization of straight chain or mildly branched chain aliphatic hydrocarbons of at least six carbon atoms to form aromatics. Other reactions occurring during reforming include isomerization, both of aliphatic hydrocarbons and of naphthenic hydrocarbons containing 5 and 6 carbon atoms in the ring; hydrogen transfer reactions, alkyl transfer reactions; etc.

According to the invention a natural gasoline,'or a component thereof, or the like, is subjected to conditions favoring parafiin isomerization reactions, thus providing for the formation of improved yields of isopentane at least some of which, then, is removed; remaining gasoline or remaining gasoline component is then subjected to reforming under conventional reforming conditions, resulting in an improved operation because of better yields of desired products from each of the reactions; and finally, when desired, an improved product is obtained by blending isopentane with the remaining gasoline after it has been reformed.

This invention in one of its forms accomplishes the reforming of natural gasoline in the presence of hydrogen and a platinum-containing catalyst.

Also, according to this invention, there is provided a process which comprises separating a natural gasoline charging stock into at least two fractions and processing each fraction under particular conditions of operation especially suitable for that material, as later described, to obtain an improved final product.

" ice Usually, the natural gasoline has been debutanized, as well as deisopentanized, but will contain. normal pentane in substantial proportions. Also, C and heavier hydrocarbons have been removed to deoil the gasoline. Thus, in one embodiment, the present invention relates to a process for reforming natural gasoline which comprises subjecting this gasoline after it has been debutanized, deisopentanized and deoiled, to conversion under paraffin isomerization conditions in the presence of a platinum reforming catalyst and then to conversion at conventional reforming conditions in the presence of a platinum reforming catalyst.

According to one concept of the present invention, the platinum reforming catalyst used for the paraffin isomerization can, and usually will, be a more active catalyst than the conventional platinum reforming catalyst. According to another concept of the invention, the platinum reforming catalyst is made more active by increasing the platinum content thereof to above that found in conventional platinum catalysts.

Another manner of increasing the activity of the catalyst is adding more fluorine thereto or by providing a more active silica-alumina base when one is employed. A combination of two or more of these means to increase catalyst activity can be used according to the invention. A greater amount of isopentane is produced by the process described in this embodiment than is normally produced at conventional reforming conditions. Also, it is possible to use rather low temperatures which, relatively speaking, are mild when compared with prior art operation.

In a second embodiment, the invention provides a process whlch comprises fractionating a debutanized, deisopentanized, deoiled natural gasoline into a normal pentane fraction and principally a C and heavier fraction; isomerizing the normal pentane using a more active than normal reforming platinum-containing catalyst at a reaction temperature of approximately 700-800 F.; deisopentanizing the effluent; recycling the normal pentane to the isomerizer; reforming the C and C,- fraction under conventional platinum reforming conditions and combining the reformed fractionwith the isopentane obtained from the isomerizer. The minimum platinum content of the catalyst will be about 0.6 percent. Preferably at least about 0.8 percent by weight of the catalyst will be platinum. The temperature with such a catalyst will not be in excess of about 800 F. when pentane or a pentanecontaining stream is isomerized.

Another embodiment of this invention relates to a process which comprises fractionating a debutanized, deisopentanized, deoiled natural gasoline into a normal pentanehexane fraction and principally a C fraction, isomerizing the normal pentane-hexane fraction as described in the previous paragraph, for normal pentane alone, and reforming the C fraction by conventional means. The reformed gasoline can be blended with the isopentane thus produced.

Thus, it will be seen that one of the features of the present invention involves separating out isopentane or a fraction containing the same before the remainder of the gasoline or fraction thereof is subjected to further conversion or reforming.

The hydrocarbon stocks that will be converted in accordance with my process comprise hydrocarbon fractions containing naphthenes and paraffins. This preferred class includes straight-run gasolines, natural gasolines, and the like. The gasoline may be full boiling range gasoline having an initial boiling point of from about 50 to about F., and an end boiling point within the range of from about 325 to about 425 F., or it may be a selected fraction thereof. The preferred fraction of natural gasoline is one containing principally normal pentane, and

hexane and heptane fractions.

The use of a more active catalyst in the first step of the process permits the useof lower temperatures. The for mation of isopentane by the isomerization of normal pentane is thermodynamically favored by the use of the lower temperatures. Therefore, the invention, which provides for lower temperatures in the first step, with removal of isopentane following said step, results in increased isopentane which, when blended together with the remainder of the gasoline, when it has been reformed, will increase the qualityof the final product. The removal of isopentane intermediate the steps of the process is an important feature of the present invention. This isopentane is not desirably passed into the reforming of the said remainder of gasoline.

Any conventional platinum or palladium reforming catalyst can be used in the first reactor. Such a catalyst can also contain a halogen such as chlorine or fluorine and can be prepared by combining a halogen with, say, alumina, in, say, a proportion of about 0.1 percent to about 8 percent by weight of said alumina, on a dry basis, commingling a platinum-containing solution with the halogen-containing alumina and calcining. A preferred catalyst for use in isomerization step of the invention will contain more than about 0.6 weight percent of platinum, but usually are not more than about 1.5 weight percent; from about 0.4 to 2 weight percent fluorine and the re mainder of the catalyst will be said more active base. This base usually is a synthetically produced hydrocarbon cracking catalyst or a component thereof.

The preparation of the base or cracking catalyst or component can be variously accomplished. Such preparations are described in the prior art. The cracking component may comprise any suitable cracking catalyst, natural or synthetic, and includes various aluminum silicate's which can be acid-treated or synthetically produced cracking catalysts such as silica-alumina, silica-aluminazirconia, silica-zirconia, and combinations of silica with magnesia, alumina, thoria, boria, etc. The specific steps of preparation may include separate sequential or coprecipitation operations which are also described in the art. One such operation is accomplished by commingling an acid such as hydrochloric acid with commercial water glass to precipitate silica, washing with acidulated water to remove sodium and commingling with, say, aluminum sulfate following which ammonium hydroxide is added and the mass thus obtained dried and thermally decomposed to obtain the desired oxide or oxides. As noted, other methods can be employed to prepare the cracking component which ordinarily is calcined at a temperature within the range of from about 500 to 1400 F. before the platinum or palladium is admixed therewith.

In the second step, or steps in which the gasoline, from which a substantial proportion of isopentane has been removed, is reformed, the catalyst can be a conventional reforming catalyst, as already described, or as available in the art. A catalyst for reforming the gasoline or fraction from whichthe isopentane has been removed, according to this invention, will be one which contains from about 0.01 to about 1 weight percent platinum and from about 0.1 to about 8 percent fluorine or chlorine upon an active silica-alumina base or a cracking catalyst component. However, here, as before noted, the active base or the cracking component of the catalyst can be either a naturally occurring or synthetically produced material. Thus, naturally occurring cracking catalysts include various silicates such as aluminum silicates, which may have been acid treated to increase their activity. Also, the cracking component can be a silica-alumina, silica-alumina-zirconia, a silica-zirconia, silica-magnesia, silicamagnesia-alumina, silica-alumina-thoria, alumina-boria, etc., which have been synthetically produced by known methods. Such methods include successive impregnation, coprecipitation, trituration, etc.

In the lieu of platinum in the catalyst, palladium can be employed. Also, mixtures of platinum and palladium can be employed. Ordinarily, the cracking component is dried at a temperature of from about 350 to about 500 F., and is then calcined at a temperature of from about 500 to about 1400 F., before admixing or otherwise adding the platinum thereto. One method of adding the platinum or palladium to the cracking component is to add it to the dry cracking component in the presence of ammonium hydroxide, say, by commingling chloroplatinic acid with ammonium hydroxide to form a mixture of pH within the range of from about 5 to about 10 and then commingling this mixture with the preformed particles of the cracking component or base. Other methods of forming the catalyst, as described in the art, can be employed.

The reforming reactions of the invention are generally endothermic; therefore, the reaction streams passing between the reaction zones are reheated to a desired temperature.

The operating conditions in the first reactor, as noted, are maintained favorable for paraffin isomerization with little naphthene dehydrogenation. The conditions in the isomerization step of the process usually will be: a temperature from about 700 to about 800 F., a pressure of from about to about 750 p.s.i.g., a liquid hourly space velocity of from about 0.2 to about 20, and a hydrogen to hydrocarbon ratio of from about 0.2 to 5 to 10 or more mols of hydrogen per mol of hydrocarbon. Conditions outside the ranges here given are within the scope of the invention to the extent that they function in a combination of steps here claimed to provide the beneficial results here set forth.'

Reforming operations in the second and third reactor ordinarily will be conducted at temperatures of from about 800 to about 1000 F., preferably 850975 F., pressures within the range of from about 100 to about 1000 p.s.i.g., preferably about 200-700, with a liquid hourly space velocity of from about 0.2 to about 20. The amount of hydrogen charged along with the hydrocarbons usually will be from about 0.5 to about 15 mols per mol of hydrocarbon and preferably 6 to about 10 mols hydrogen per mol of hydrocarbon.

According to the invention, the isomerization is operated at a lower temperature (700800 F.) than the reforming (800-1000 F.) and, as noted, a more active catalyst is used for isomerization than the conventional reforming catalyst. This use of a more active platinum reforming catalyst in the isomerization step permits an increase in the isomerization of the normal pentane obtained and permits the use of lower temperatures.

In Figure l of the drawings there is shown diagrammatically an embodiment of the invention in which in the first step only one reactor is employed and in which the second step or stage is conducted in two reactors in series arrangement. A fractionator is shown for the intermediate removal of the isopentane, according to the invention. In Figure 2, a normal pentane-containing stream and a hexaneand heptane-containing stream, which can be obtained by fractionating a single feed to the unit according to the invention, are, respectively, isomerized and reformed, the products of the two steps being then blended together.

Referring now to Figure 1 of the drawing, a natural gasoline which has been debutanized, deisopentanized and deoiled is passed through a heater (not shown) wherein it is raised to a temperature of about 750 F. Hydrogen is mixed with the heated gasoline in the approximate mol ratio of 1:1 and the mixture is passed through lines 11 and 12 into the isomerization reactor 13 which contains the catalyst which has approximately the following composition by weight: 0.7 platinum, 0.8 fluorine and the remainder consisting essentially of the silica-alumina base, as described, for isomerization. This catalyst, as noted, can be a conventional platinum reforming catalyst or, as preferred, according to the invention, is a more active platinum reforming catalyst, also as previously described. The gasoline along with hydrogen is passed through the reactor 13. In the example here illustrated, the catalyst is deposited as a fixed bed in reactor 13. It is to be understood that any other suitable manner of intimately contacting the reactants with the catalyst can be employed. The pressure in reactor 13 is about 300 p.s.i.g. and liquid hourly space velocity is about 0.3. The effluent from reactor 13 is passed through line 14 to hydrogen separator 15 wherein ordinarily all the hydrogen is removed through line 16 and recycled to reactor 13. The balance of the effluent is passed through line 17 to a fractionator 18, wherein the efiluent is deisopentanized. The isopentane is removed through line 19 for outside use such as blending with a reformed gasoline, in this instance the reformed gasoline of the embodiment, in a blending vessel not shown. The bottoms from fractionator 18 is removed through line 20 and the temperature raised to about 850 F. in a heater (not shown) and passed together with hydrogen from line 21 to reactor 22. The reformed gasoline from reactor 22 is passed through line 23, heated, and into reactor 24. The reforming catalyst deposited in reactor 22 and 24 has the following composition: 0.41 weight percent platinum, 0.24 weight percent fluorine, 0.23 weight percent chlorine, about 0.10 weight percent silica, and the balance alumina. In the case here illustrated, the catalyst is deposited as a fixed bed in reactors 22 and 24 but it is understood that any other suitable manner of intimately contacting the reactants with the catalyst may be used. A pressure of about 280 p.s.1'.g. and a liquid hourly space velocity of about 0.3 are employed in reactors 22 and 24. The

amount of hydrogen charged along with the hydrocarbons is maintained in the range of 6 to about 10 mols hydrogen per mol of hydrocarbon, though in some instances, this ratio can vary in the range of from 0.5 to about 15.

The distribution of hydrogen to reactors 13, 22, and

. 24 is controlled to maintain the desired hydrogen concentration in each of these reactors. Preferably a greater hydrogen concentration is maintained in reactors 22 and 24 than in reactor 13. When the supply of hydrogen in the process is not sufficient, additional hydrogen is introduced from an extraneous source through line 25. When the amount of hydrogen produced in the process is in excess of that desired, the excess hydrogen is removed from the process'by way of line 25.

Ordinarily little or no hydrogen will be made in reactor 13 and for this reason, all of the hydrogen from separator 15 will be recycled through line 16. Since, ordinarily, the hydrogen from reactors 22 and 24 will be sufficient to supply the hydrogen for reactor 13, the makeup hydrogen. for reactor 13, when supplied. through line 25, can come from the separation of hydrogen from the reformate, now mentioned.

The reformate is removed from reactor 24 through line 26 for subsequent separation and recovery (not shown). Usually this separation will include stabilization of the gasoline to produce a final gasoline of desired vapor pressure.

When isopcntane is to be blended with the reformate, it can be introduced into admixture therewith by way of line 27 to the extent or in proportion, as desired.

pentane is blended with a C -C reformate obtained from said C -C fraction over a conventional platinumreforming catalyst.

The following data show the gain obtained upon increasing the platinum content of the catalyst from 0.4 to 0.8 weight percent platinum.

A conventional catalyst of the platinum-reforming type contains about 0.4 to about 0.6 weight percent platinum.

Platinum, wt. percent 0. 4 O. 8 Pressure, p.s.i.g 150 150 Temperature, F 820 820 LHSV 3 3 11 /110, mol 3 3 11-0 conv rsion, wt. 51 54 Selectivity, wt. perccnt 88 90 Yield of i-C wt. percent r 45 49 From the foregoing data, it will be noted that the conversion of normal pentane, the selectivity and the yield of isopentane obtained with the catalyst containing 0.8 Weight percent platinum are considerably and importantly higher than those obtained with the catalyst containing 0.4 weight percent platinum.

The foregoing data illustrate the importance of increasing the platinum content in the catalyst in the first step.

Research+$ Research TEL Clear Natural Gasoline 90. 0 72.7 Feed, Dcisonentanized Natural Gasoline 84.0 6%.1 0 Product (93.6 vol. percent yield) 92. 6 78. 6

lBlending the isopentane from the fractionation back with the C product gave a 95.4 overall liquid volume percent yield of product having a Research +3 TEL rating of 96 (calculated). Data for this workare in Tables I and II hereinafter.

TABLE I Delsopentamzatzon 0 natural gasoline Normal Fraction Iso- Pentane Natural pentane and Heavier LV Percent of Natural Gasoline 27. 8 72. 2 100.0

Composition, Wt. percent:

Butane 7. 8 Iso pentane 87. 0 Normal Pentane 5. 2 05+ 0. 0

Total 100.0 100.0

API Gravity (60 F.) 96.4 78.3 82. 8 RVP 22.20 9. 50 12. ASTM Distillation:

I13 79 108 95 79 110 103 79 123 106 79 125 109 80 129 112 81 133 116 82 139 122 83 146 84 139 85 169 155 87 186 181 87 200 199 137 246 254 Recovered, percent 96. 2 98. 2 98.0 Residue, percent 0. 4 0, 4 Loss, percent 3. 8 1.4 1. 6 Octane Rating:

Research+3 n11. TEL- 104. 0 84. 0 90. 0 Research, Clear 92.1 65.1 72.7

7 TABLE II Reforming of deisopentanized natural gasoline Process conditions:

Temp., F 7

Average 877 Preheat 888 Bottom of bed 887 Liquid sp. vel., vol./cat. vol./hr. 3.1 Hydrogen/ naphtha, mol ratio 6.5 Pressure, p.s.i.g 500 Product yields, wt. percent of feed:

H2 0.]. CH C55 0 5 CgS 1 8 C4S iC 20.6 nC 21.8 C 51.7

Total 100.0

C Product:

Yield, LV percent 93.6 API gravity (60 F.) 77.4 RVP 10.75 ASTM distillation-- IBP 101 5% 114 10 116 20 120 30 124 40 128 50 134 60 140 70 151 80 164 90 185 95 206 EP 266 Recovered percent 97.7 Residue percent 0.5 Loss percent 1.8 Octane rating Research +3 ml. TEL 92.6 Research, clear 78.6

It will be apparent to one reading this disclosure that the catalysts employed in the several steps of the process can be various and different and, therefore, in respect of the combination of steps claimed, it is not limited to any particular catalyst except as in the claims. However, the now preferred catalysts have been described and to this extent, their combination with the remainder of the steps is a part of the claimed invention.

Although the preferred catalyst for the first step of the invention will usually contain more than about 0.6 weight percent of platinum, it is possible, in a broader view of the operation to employ in said step a catalyst containing from about as low as 0.01 percent platinum to about 1 percent platinum by weight of the final catalyst as used. I

Referring to Figure 2 of the drawing, a heated m xture of hydrogen and normal pentane is passed through l1ne 30 into the isomerization reactor 31. Reactor 31 contains a catalyst comprising about 0.6 Weight percent platinum and 0.6 weight percent fluorine on alumina. The operating conditions are a total pressure of 500 p.s.1.g., a liquid hourly space velocity of 4 and a temperature of 700-800 F.

The etfluent from reactor 31 is withdrawn through line 32 to a hydrogen separation Zone 33. Hydrogen is removed through line 34 and recycled to reactor 31. The balance of the effluent is removed through line 35 to fractionator 36'wherein isopentane is removed overhead through lines 37 and 38 to be blended with normal pentame and the C and C reformate. Normal pentane is removed from the fractionator 36 through lines 39 and 30 back to the isomerization reactor 31 or part of the normal pentane may be removed if desired through lines 39, 40 and 38 to be blended with isopentane and the C and C reformate. A heater (not shown) is required to heat the recycle normal pentane to the reactor 31.

The C and 0, fraction is passed through line 41 and is joined by a stream of recycle hydrogen flowing through line 42. The commingled streams are passed through a heater (not shown) wherein they are heated to the desired temperature and through line 43 into reactor 44.

Reactors 44 and 45 each contain a bed of platinum reforming catalyst comprising about 0.3 percent platinum and 0.1 percent fluorine on alumina and the conditions therein are a pressure usually in the range 300-700 p.s.i.g., a hydrogen/hydrocarbon ratio of 5:1, a temperature in the range from about 850 to about 975 F., and a liquid hourly space velocity of about 4.

The effluent from reactor 44 is withdrawn through line 46 through a heater (not shown) into reactor 45. The operating conditions in reactors 44 and 45 are approximately the same. The eflluent from reactor 45 is withdrawn through line 47 to a hydrogen separation zone 48, wherein hydrogen is removed through line 49 and recycled to reactor 44 or a portion transferred through lines 49, 34 and 30, to reactor 31. When the supply of hydrogen in the process is not sufficient, additional hydrogen may be introduced from an extraneous source through line 50. On the other hand, when the amount of hydrogen produced in the process is in excess of that desired, the excess hydrogen may be removed from the process by way of line 50.

The C and C reformate is withdrawn from zone 48 through line 51 for subsequent separation and recovery (not shown). Usually this separation will include stabilization of the gasoline to produce a final gasoline of desired vapor pressure.

As noted earlier herein, the respective feeds to reactors 31 and reactor 44 can be a pentane-containing stream and a hexane and heptane-containing stream obtained by way of a fractionation of a single feed to the unit. Such a fractionation is not shown in the drawing for sake of simplicity. Clearly, it is the essence of the invention to treat separate streams, as described, derived from a natural gasoline in a manner as described herein and as set forth in the drawings.

An embodiment of this invention is, as noted, a process which comprises fractionating a debutanized, deisopentanized, deoiled natural gasoline into a normal pentane-hexane fraction overhead and principally a heptane bottom fraction, isomerizing the normal pentane-hexane portion and reforming the heptane fraction by conventional means.

In the reforming of natural gasoline one of the principal desirable reactions is isomerization of the normal pentane and normal hexane. When platinum-containing catalysts are used, increased isomerization of the normal pentane and normal hexane can be obtained by segregating a normal pentane-hexane fraction and a heavier fraction, contacting the normal pentane-hexane fraction with a higher acidity platinum catalyst and the heavier fraction with a lower acidity catalyst. The use of a higher acidity catalyst gives isomerization of the normal pentane-hexane because the catalyst is more active and tends to give more isomerization at any temperature and also because the more active catalyst permits the use of lower temperatures at which the formation of branched pentane and hexane hydrocarbons is thermodynamically favored. The lower acidity catalyst is desirable with the heavier fraction because it gives more eflicient conversion of naphthenic hydrocarbons to aromatics. When platinum-fluorine-alumina catalysts are used, it is preferable to have about 0.4 to 1.0"percent fluorine in the Catalyst 1 2 m m Fluorine.

Composition; wt. percent:

Alumina 9:

Tatar..." 1c.

The compositions of the xylene-ethylbenzene fractions of the products are an index of the isomerization activity of the catalysts. Catalyst 1 (higher fluorine) gave a larger amount of isomerization, even at lower temperature, as is shown by the following data.

yl Ethylbenzene 19.

The data show that catalyst 1 gave higher isomerization of ethylbenzene to xylenes.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, drawings and the appended claims to the invention, the essence of which is that a natural or straight-run gasoline or a component thereof, specifically a pentane-containing stream, is subjected to conditions favoring isomerization of paraffin hydrocarbon therein; in one form of the invention, the reforming of pentane in a stream containing it being acc omplished employing a more active platinum reforming catalyst, as described, at a temperature not in excess of about 800 F.; preferably after debutanization, deisopentanization and deoiling; the isomerized gasoline or component thereof constituting said stream is fractionated to remove isopentane therefrom and the remainder of the gasoline or component thereof is reformed in at least one embodiment of the invention, the isopentane and reformed remainder are blended together in a proportion, as desired, to obtain, from the process, improved yields of isopentane from at least one of the isomerization and the reforming steps and an improved product, as described. Herein and in the claims, platinum and palladium are considered to be functionally interchangeable.

I claim:

1. A process for up-grading a natural gasoline containing pentane in which process it is desired to obtain high octane value reformed gasoline product formed in a reforming zone in the absence of substantial amounts of normal pentane contained in said gasoline which comprises in a first step subjecting the gasoline to conditions favoring paraffin isomerization reactions thus providing for the formation therein of improved yield of isopentane from normal pentane contained therein thus substantially reducing the normal pentane content of said natural gasoline, removing a substantial portion of isopentane from the thus treated gasoline thus obtaining a remaining gasoline substantially freed from normal pentane and isopentane and then subjecting the remaining gasoline to reforming conditions to reform the same.

2. A process according to claim 1 wherein at least a portion of the removed isopentane and at least a portion 10 of the said remaining gasoline which has been reformed are blended to produce a gasoline product.

3. A process for up-grading a gasoline selected from the group consisting of natural and straight-run gasolines in which process it is desired to obtain high octane value reformed gasoline product formed in a reforming zone in the absence of substantial amounts of normal pentane contained in said gasoline which comprises debutanizing, deisopentanizing and deoiling said gasoline, then subjecting said gasoline to conditions favoring isomerization of normal pentane therein so as to isomerize a substantial portion of said pentane to isopentane thus substantially reducing the normal pentane content of said natural gasoline, separating a substantial quantity of said isopentane from said gasoline thus obtaining a remaining gasoline substantially freed from normal pentane and isopentane, subjecting the remainder of the gasoline to reforming conditions so as to reform the same thus obtaining as products of the process isopentane and a reformed gasoline which can be blended together to give an improved gasoline product.

4. A process according to claim 3 wherein in the first treating step a temperature in the approximate range 750 to 800 F., a pressure in the approximate range of 250 to 750 p.s.i.g. and a liquid hourly space velocity of 0.2 to about 5 are employed in the presence of .a catalyst which will favor isomerization of pentane to isopentane under the said conditions.

5. A process according to claim 4 wherein hydrogen is employed in a molar ratio of hydrogen to hydrocarbon of from about 0.2 to about 5 mols of hydrogen per mol of hydrocarbon.

6. A process according to claim 5 wherein the catalyst in said step wherein pentane is isomerized to isopentane contains from 0.6 to about 1 weight percent platinum, and from about 0.4 to about 2 Weight percent fluorine upon an active silica-alumina base,

7. A process according to claim 3 wherein in said reforming step a temperature in the range of from about 800 to about 1000 F., a pressure within the approximate range of 250 to 1000 p.s.i.g., a liquid hourly space velocity of 0.2 to about 20 and a mole ratio of hydrogen to hydrocarbon of from about 0.5 to about 15 are employed.

8. A process according to claim 7 wherein in said reforming step a catalyst containing from about 0.01 to about 1 weight percent platinum and from about 0.1 to about 8% fluorine upon an active silica-alumina base is employed.

9. A process for upgrading a natural gasoline in which process it is desired to obtain high octane value reformed gasoline product formed in a reforming zone in the absence of substantial amounts of normal pentane contained in said gasoline which comprises subjecting said gasoline to isomerization conditions thus isomerizing its pentane content therein to isopentane thus substantially reducing the normal pentane content of said natural gasoline, reforming a fraction of said gasoline which contains hydrocarbon higher boiling than pentane and from which substantially all pentane has been removed and blending together the isopentane and reformed product thus obtained.

10. A process for upgrading the gasoline selected from the group consisting of a natural gasoline and a component thereof which comprises in a first ste subjecting the same to conditions favoring parafiin isomerization reactions thus providing for the formation of improved yield of isopentane from normal pentane therein contained, removing the isopentane from the thus obtained product and then subjecting the remainder of the product to reforming conditions to reform the same.

11. A process according to claim 10 wherein at least a portion of the removed isopentane and at least a portion of the remaining product are blended to produce a final product.

12. In a hydrocarbon conversion operation in which a fraction containing normal pentane is first isomerized and the fraction then reformed, the improvement which comprises substantially removing isopentane produced in said isomeriza'tion before conducting the reforming and then conducting the said reforming upon the remainder of said isomerized fraction.

13. A process for the improvement of a gasoline selected from the group consisting of a debutanized natural gasoline and a straight run gasoline which contain normal pentane comprising contacting said gasoline at a temperature in the range of 700 F. to 800 F. with a supported platinum isomerization catalyst containing at least about 0.6 percent platinum by weight of the catalyst and a halogen selected from the group consisting of chlorine and fluorine in the range of 0.1 to 8 percent by weight of the support, separating the isopentane from the efiluent, contacting any unconverted normal pentane and higher boiling gasoline components remaining after the separation of isopentane with a platinum-containing reforming catalyst under reforming conditions including a higher temperature in the range of 800 to 1,000 F. whereby additional isopentane is produced and the octane number of the higher boiling fraction is increased.

14-. A process according to claim 1 wherein in the first step the catalyst is a platinum catalyst containing at least about 0.7 percent by weight platinum, about 0.8 percent by weight fluorine, the remainder consisting essentially of a hydrocarbon cracking catalyst base.

15. A process according to claim 14 wherein the platinum-containing catalyst in the reforming step contains 0.011 percent by weight of the catalyst of platinum and 0.18 percent by weight of said halogen upon an active cracking catalyst component.

16. A process according to claim 1 wherein the isomerization conditions include a temperature in the range 700 F.-800 F. and the reforming step is conducted at a temperature in the range 850 F.975 F. at a pressure in the range l001,000 p.s.i.g., a liquid hourly space velocity of 0.220 and 0.5-15 mols hydrogen per mol of hydrocarbon is present.

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1. A PROCESS FOR UP-GRADING A NATURAL GASOLINE CONTAINING PENTANE IN WHICH PROCESS IT IS DESIRED TO OBTAIN HIGH OCTANE VALUE REFORMED GASOLINE PRODUCT FORMED IN A REFORMING ZONE IN THE ABSENCE OF SUBSTANTIAL AMOUNTS OF NORMAL PENTANE CONTAINED IN SAID GASOLINE WHICH COMPRISES IN A FIRST STEP SUBJECTING THE GASOLINE TO CONDITIONS FAVORING PARAFIN ISOMERIZATION REACTIONS THUS PROVIDING FOR THE FORMATION THEREIN OF IMPROVED YIELD OF ISOPENTANE FROM NORMAL PENTANE CONTAINED THEREIN THUS SUBSTANTIALLY REDUCING THE NORMAL PENTANE CONTENT OF SAID NATURAL GASOLINE, REMOVING A SUBSTANTIAL PORTION OF ISOPENTANE FROM THE THUS TREATED GASOLINE THUS OBTAINING A REMAINING GASOLINE SUBSTANTIALLY FREED FROM OBTAINING A REMAINING PENTANE AND THEN SUBJECTING THE REMAINING GASOLINE TO REFORMING CONDITIONS TO REFORM THE SAME. 